REACTION OF SORGHUM VULGARE VAR. TECHNICUM KÖRN. IN THE EARLY GROWTH STAGES OF DEVELOPMENT IN DROUGHT AND WATER DEFICIENCY IN LABORATORY CONDITIONS

Stanimir Enchev, Plamen Marinov-Serafimov, Irena Golubinova

Abstract: The effect of polyethylene glycol PEG-20000 on the induction of water stress on germination and the initial development of five genotypes (varieties and local populations) Sorghum vulgare var. technicum [Körn.] was determined under laboratory conditions at the Institute of Forage Crops – Pleven. In order to simulate the water deficit induced by osmotic stress, different concentrations (1.25%; 2.5%; 5.0%; 7.5%; 10.0%; 12.5%; 15.0%; 17.5% and 20.0%) of non-ionic water soluble polymer polyethylene glycol of molecular weight 20000 (PEG – 20000) were used in the study. It was found that: Osmotic stress induced by the addition of PEG inhibits root growth and shoot IR% from 15.03 to 72.29% at higher applied concentrations (from 10.0 to 20.0%). Lower applied concentrations (1.25 to 7.5%) had a stimulating effect IR% from 11.71 to 135.77% according to control treatments for all tested genotypes. There was a specific variety reaction with regard to the effect of PEG on seedling growth (cm) and formation of fresh weight on seedlings (g) in the tested genotypes Sorghum vulgare var. technicum (Körn.). It was found that with relatively good tolerance to osmotic stress it is possible to determine Szegedi 1023 variety and the AS17P local variety (TI average varied from 2.28 to 2.55). With low coefficients of tolerance, i.e. the high sensitivity of drought in the early growth stages of development (BBCH – 09-10) were the G16V and MI16N local varieties (TI average varied from 1.29 to 1.36) while GL15A local variety occupies an intermediate position – TI – 1.62. In the Szegedi 1023 variety and AS17P local variety, unlike the growth of the seedlings, the formed fresh biomass in g for one seedlings increases with the increasing level of PEG 20000 treatments, except for the highest applied concentra¬tions (17.5 and 20.0%), while the GL15A, G16V and MI16N local varieties formed fresh biomass of the roots, shoots and seedlings decreased IR% varied from 22.22 to 100.0% and the differences were statistically significant (p = 0.05) which can be explained by their sensitivity to drought in the early growth stages of development (BBCH-09-10). The G16V and MI16N local varieties found superior and might be productive in further breeding programmes for drought tolerance.

Keywords: polyethylene glycol (PEG); seedling; Sorghum vulgare var. technicum Körn.; water stress

Date published: 2018-06-01